1. Field of The Invention
This invention relates to an electromagnetic device, and more particularly, to a contactor having an improved energizing circuit.
2. Description of The Prior Art
In large electromagnetic devices, such as DC contactors, it has been found that full wave rectified DC power from an AC power source can be applied to an energizing coil of the contactor in order to supply sufficient electromagnetic energy to insure complete closure of the main power switches, which switches are comprised of respective pairs of stationary and movable contacts. However, once the contacts of the contactor are brought into final engagement, it is no longer necessary to apply full-wave rectified DC power to the energizing coil in order to maintain the contacts in a sealed position. If a holding resistor is inserted in series with the energizing coil after the coil has been energized, in order to reduce the applied energy to the coil, the resistor would have to be quite large in physical dimension, and would also dissipate and waste an unnecessary amount of power.